To estimate the risk of dementia associated with post-stroke epilepsy.
Cognitive impairment and dementia are leading causes of post-stroke disability, and are also associated with epilepsy. However, the risk of dementia associated with post-stroke epilepsy is unknown.
Data from 14,493 Atherosclerosis Risk in Communities (ARIC) Study participants without stroke or dementia at baseline (1987–1989) were analyzed through December 31, 2022. Adjudicated stroke and International Classification of Diseases Ninth/Tenth Revisions (ICD-9/10) code-defined epilepsy events were modeled as a 4-level time-varying exposure (no stroke/no epilepsy; stroke only; epilepsy only; post-stroke epilepsy). Adjudicated dementia was defined using data from neuropsychological tests, informant interviews, hospitalization ICD-9/10 and death certificate codes. Fine and Gray proportional hazards models adjusted for sociodemographics and vascular risk factors to account for the competing risk of death were used to estimate the risk of dementia associated with post-stroke epilepsy.
At study baseline, the mean age of participants was 54.3 years, 55% were female, and 27% were of Black race. Over a median of 26 years, 1,191 (8.2%) patients had an incident stroke, 759 (5.2%) patients developed epilepsy, and 139 (1.0%) patients developed post-stroke epilepsy. A total of 3,697 incident dementia cases occurred over a total of 317,796 person-years of follow-up. The risk of dementia in the post-stroke epilepsy group was 2.43 times (95%CI=1.96-3.02) the risk of dementia in the no stroke/no epilepsy group. The risk of dementia among individuals with post-stroke epilepsy was also significantly higher compared to the stroke only (HR=2.04, 95%CI=1.61-2.58) and epilepsy only (HR=1.63, 95%CI=1.28-2.07) groups.
The risk of dementia was increased after post-stroke epilepsy compared no stroke and no epilepsy and compared to stroke alone and epilepsy alone. This work identifies individuals with post-stroke epilepsy as a high-risk subpopulation that may benefit from closer clinical monitoring for cognitive changes.